If we examine the connection operation among pipings in earlier times, such as bamboo pipes which were connected to a supply water, you would occasionally see water leakage and bad pipe connections which would cause water loss in large volume. The reason was simply that, because of the lack of modern materials and machines, the connection components were too simple to tightly seal and connect the pipes.
If we check the piping connections currently applied in the market, connection parts for plastic pipe and metal pipe, we would often discover the methods employed to connect such pipes were mainly focused on sealing oil, tapped threads, tape seal, etc., even though they were developed as a contemporary product having research background.
Should the fittings' connection or disassembly be conducted outside the factory for maintenance purposes, we must find an alternative material to seal the gaps between the connected pipes. Therefore, rubber gaskets, rings or conical ring sockets, etc., possessing elasticity were invented. These take advantage of their compressible properties to prevent the occurrences of fissures while connecting the pipes, as shown in FIGS. 1, 2 and 3. However, the sealing effect developed by these gaskets, rings or conical sockets depends on the compression force of pipe itself or the tightness of externally fastened bolts and nuts to achieve the compression sealing effect.
These type of rubber parts utilized for connecting pipes must be compressed and deformed to seal the fissures of the connected pipes. The reason why they can be deformed to seal the connected pipe is entirely dependent upon the fittings' compression force or the tightness of fastening bolts and nuts. In a passive state, no individual contribution can be made by these rubber parts. The aforementioned alternatives make it very difficult to reach an absolutely sealed state due to vibration or other factors which may cause loosening of the pipe fitting. They are the biggest weaknesses of the pipe connection operation.